CRP or ESR: when to use which inflammation marker?

CRP or ESR? If you see both on your result, or have to choose, the logical question is which one fits best. Short answer: it depends on the situation, and often they are most useful together. CRP reacts fast to recent inflammation, while ESR is slower and shows longer-running processes (Harrison 2015). In our experience it is not a matter of better or worse, but of the right tool for the right question.

This article belongs to the overview about inflammation markers in your blood and helps you tell the two apart.

How do CRP and ESR differ?

The biggest difference is speed and specificity. CRP is a protein your liver makes within hours and that falls fast again. ESR indirectly measures how fast your red cells settle, which changes only after a day and stays raised longer. CRP is also less sensitive to age and sex, while ESR rises with the years. Read the basics on the CRP and ESR pages.

When does which value fit?

hs-CRP stands apart here: it is the sensitive variant of CRP for your heart, covered in hs-CRP and heart risk. For ordinary inflammation you usually do not need that extra sensitivity.

Why are they often requested together?

Because they react at a different pace, the combination gives more information than each alone. A high CRP with a still-normal ESR fits something acute. A raised ESR with a normal CRP can point to a longer-running process. Laying those two patterns side by side says more than one value.

Imagine your GP wants to know whether your persistent joint complaints involve inflammation. Drawing CRP and ESR together shows whether the picture looks acute or chronic, which helps the next step without the values themselves giving a diagnosis.

What do you choose?

If you want to test without a referral, you do not have to make that choice alone. A broad check usually includes both markers. At Vitalcheck you can choose the basic health checkup or, for a broader view, the extended health checkup. If a value is off, discuss it with your GP, and see also raised CRP without symptoms. Every result is reviewed by a BIG-registered doctor.

References

• Harrison M. Erythrocyte sedimentation rate and C-reactive protein. Aust Prescr. 2015. PMID: 26648629.
• Sproston NR, Ashworth JJ. Role of C-Reactive Protein at Sites of Inflammation and Infection. Front Immunol. 2018. PMID: 29706967.
• Thuisarts.nl. About blood testing.

Every blood test result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.